Move ranker_model_loader to a new component.

components/ranker/BUILD.gn

Index: components/ranker/BUILD.gn
diff --git a/components/ranker/BUILD.gn b/components/ranker/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..cbb1346220d3c46aab6d6fee4cec8b9883aa591b
--- /dev/null
+++ b/components/ranker/BUILD.gn
@@ -0,0 +1,39 @@
+# Copyright 2017 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+static_library("ranker") {
+  sources = [
+    "ranker_model.cc",
+    "ranker_model.h",
+    "ranker_model_loader.cc",
+    "ranker_model_loader.h",
+    "ranker_url_fetcher.cc",
+    "ranker_url_fetcher.h",
+  ]
+
+  deps = [
+    "//base",
+    "//components/data_use_measurement/core",
+    "//components/ranker/proto",
+    "//net",
+    "//url",
+  ]
+}
+
+source_set("unit_tests") {
+  testonly = true
+
+  sources = [
+    "ranker_model_loader_unittest.cc",
+    "ranker_model_unittest.cc",
+  ]
+
+  deps = [
+    ":ranker",
+    "//base",
+    "//components/ranker/proto",
+    "//net:test_support",
+    "//testing/gtest",
+  ]
+}